Red rhodamin dye.



Nrrn States JOIIANN JAKOB BRACK, OF BASLE, SWITZERLAND, ASSIGNCR TOBASLE CHEMICAL l/VORKS, OF SAME PLACE.

RED RHODAIVHN DYE.

SPECIFICATION forming part of Letters Patent No. 643,371, dated February13, 1900. Application filed November 28,1899. Serial No. 738,668.(Specimens) T0 (tZZ whom it may concern.-

Be it known that I, J OHANN J AKOB BRACK,

chemist, a citizen of the Swiss Republic, re-

methylamidooxybenzoylbenzoic acid and metaamidoparacresol (CH :NI-IOI-I:1:2:4) is described. I have now found that by considing at Basle,Switzerland, have invented densing two molecules of the said ether witha new Rhodamin Dye, of which the following I one molecule of formicaldehyde a new dyeis a clear and complete specification.

In Letters Patent No. 584,119, dated June 8, 1897, an alkyl ether of theunsymmetrical dimethyl-methylrhodamin derived from di can-0000,11,

The new dyestuff may be prepared as follows: To a solution of thirtykilos of the ethyl ether of the unsymmetrical dimethyl-methylrhodaminderived from dimethylamidooxybenzoylbenzoic acid and metaamidoparacresol(CH NH 011:1 2 at) in two hundred kilos sulfuric acid of 66 Baum I add amixture of twokilos formic aldehyde of forty per cent. and thirty kilossulfuric acid of 66 Baum. The reaction sets in at once and is marked bya rise of the temperature of the solution. To complete the reaction, Iallow the solution to stand for twelve hoursat the ordinary temperature,and afterward I pour it on ice. The sulfate of the product ofcondensation precipitates nearly entirely as a dark-brown-red granulousmass. To convert this sulfate into chlorid, I dissolve the former in onehundred kilos of alcohol and one hun dred and thirty kilos of water andadd to the hot solution sixty kilos of hydrochloric acid of 20 Baum.After cooling, water is poured in while stirring,whereby the chlorid isnearly entirely separated as darkred precipitate, which is separated byfiltration and dried.

In its dry state the new dyestuff appears as a red-brown powder, whichdissolves in hot water and alcohol. It dyes tannin-mordanted cotton infiery-red tints, which are yet bluer than those obtained with the ma- Istuff is obtained dyeing tannin-mordanted cotton in fiery-red tints.This new dyestuff probably has the following constitutional forni ula:

onnooc-c rr terial at starting. Its solution in hot water is crimson redand shows no fluorescence, differing in this respect from the materialat starting.

In concentrated sulfuric acid the dyestuff dissolves with an orangetint, which turns to crimson red by addition of water.

By addition of water to a solution of the dyestuff in concentratedsulfuric acid a darkred precipitate separates after a short time fromthe'solution. By adding hydrochloric acid to an aqueous solution of thecoloring matter the color of the solution becomes bluer, and a flockyprecipitate is gradually separated, while the aqueous solution of thematerial at starting does not change on addition of hydrochloric acid.

hat I claim as my invention, and wish to secure by Letters Patent, is

A new article of manufacture, the hereindescribed rhodamin dye derivedfrom formic aldehyde and the ethyl ether of the unsymmetricaldimethyl-methylrhodamin resulting from the condensation ofdimethylamidooxybenzoylbenzoic acid with metaamidoparacresol (CH N11,:OH:1:2:4=), the said rho damin dye dyeing taunin-mordanted cotton infiery-red tints bluer than those obtained with the said ether andconstituting in the form of its hydrochloric salt and in dry state ared-brown powder, which is soluble in hot In witness whereof I havehereunto signed water with a crimson-red tint showing no my name, this17th day of N0vember,1899,in 1o fluorescence and dissolves inconcentrated the presence of two subscribing Witnesses. sulfuric acidwith an orange tint, which turns 7 to crimson red by addition of Water,while JOHANN JAIOB BRACK' by adding hydrochloric acid to its aqueousWitnesses:

solution, this latter becomes bluer and de- GEORGE GIFFORD,

poses gradually a fiocky precipitate. I AMAND BITTER.

